This invention pertains to the field of electrical power distribution networks, and in particular to poletop switches, which control the flow of electricity, and are mounted on electric power poles. More particularly, this invention pertains to remotely operated devices used to open and close the high voltage switches found on electric power poles.
Most commercial and residential power is distributed through electric cables which are run along a series of power poles. The power is distributed through three separate cables each of which transmits power in a different phase. These poles are mounted with a gang of high voltage electric power switches enabling the flow of electricity to be stopped when the switch is open. Poles with these ganged switches are placed strategically around a city or countryside to allow the flow of power to be diverted from a given area and rerouted to another area.
Power distribution switches are often open and closed routinely to redistribute power in response to load increases and decreases from a particular area. In some cases, the power switches must be operated in response to an unexpected power loss, or other emergency. In cases when the switches must be opened or closed, and where remotely operated switches are not in place, a crew must be dispatched to the exact location of the pole having the ganged poletop switches. The crew then operates the switches manually to open and close them as needed. Sending a crew to manually "throw" a set of ganged switches can be costly to the company responsible for power distribution. In addition, because some of the poletop switches may be located in distant areas, it may take considerable time for the crew to travel to the affected location which impacts the households or plants using the power.
To combat these problems, there have been some attempts to use mechanical actuators to open and close power switches One such device is shown in U.S. Pat. No. 3,806,679 issued to Pahl. Pahl discloses a hydraulic switch actuator which can be mounted near the bottom of a power pole to operate power line switches. The Pahl actuator includes a self-contained hydraulic cylinder and piston assembly which is attached to a crank arm that provides the movement necessary to open and close the switches. Operation of the actuator in Pahl can be performed by an operating button located near the actuator, or by remote radio signals received by the actuator.
Another mechanical actuator device is disclosed in U.S. Pat. No. 3,930,134 issued to Rostron, et al. The actuator in Rostron provides translatable movement through the use of a pneumatic piston and cylinder assembly which uses high pressure gas to generate movement of the piston. The Rostron device employs an operating rod and lever assembly to provide the actuation needed to open and close a power switch.
The prior art fails to adequately solve the problems associated with performing manual switching operations of high voltage power lines. In particular, the Pahl and Rostron patents both disclose actuators for providing controlled translatable movement which in turn operates a set of switches. However, these prior art designs are cumbersome and contain complex mechanical linkage assemblies.